This Core serves two principal functions for the Center: 1. Injury Production Activities are centralized for creating repeatable injuries of varying severity. The models used for these projects involve focal axonal injury in the guinea pig optic nerve, experimental DAI in the minipig, fluid and solid percussion in the rat, and cortical contusion in the rat. The single injury production facility will assure quality control and comparability of the injuries produced. 2. Biomechanics Research will be conducted to improve the fidelity of the various injury models and to better understand their relationships to human head injury.